Process of tanning hides and skins.



: srnrns I JIHAOHT I NOUYE, OF MINAMIKU, AND T SURUMATSU DOGURA, OF KAWAKAMI, JAPAN.

PROCESS OF TANNING HIDES AND SKINS.

Specification of Letters Patent.

Patented Jan. 21, 1908.

Application filed July 16 1907. Serial No. 384.075

To all whom it may concern:

Be it known that we, JrHAoHI Brown, of 2896 Motomachi Sanchome, Namba, Minamiku, Osaka, Japan, and 'TSURUMATSU DOGURA, of 69 Otaki, Kawakami, Yoshino,

described and ascertained in an by the fo tion.

lowing statement.

Our inventlon relates to a new process of tanning hides or skins; and the object thereof is to devise a process whichtwill accom- 'pl'ish the tanningof hides or skins "in less.

time than is required in .tanning processes now in use, and which will result in astrongcr and at the same time a more pliableleather than is produced by former tanning processes.

With the above objects in view we repare a solution composed of the following ingredicuts in substantially the proportion stated,

although it will be understood that the amount of each ingredient is subject to varia- However, a solution made up of the. ingredients in the uantities stated has been found to give the est results, and the proportion stated is the best with which we are acquainted:

Water. -100.00 parts I Ferrous sulfate 11.25

Potassium'nitrate 4.00

Potassium bichromate 1.25

A small amount of acetic acid is added if it is desired to produce a soft and extremely flexible leather.

Hides or skins to be tanned are first subjected to a preliminary preparatory treatment in general use in the art of tanning, such as to a treatment with salt, lime, pigeons dung, acetic acid, etc.; after which they are immersed in the; solution above mentioned for a period ranging from 8 to 40- hours, accordln skins to e tanned.

The pur ose'of using the above solution is to accomp ish'theaction of tanning by means of iron alum and chrome alum, which action to the condition of'the hides or is the result of a chemical reaction between the ferrous sulfate, potassium nitrate, po-

tassium bichromate, and the organic substance of the hides or skins, andwhich action is aided by the small amount of ferric sulfate and free sulfuric acid usually present in commercial ferrous sulfate.

In the use of our process above set forth a leather of greatly increased tensile strength is produced, which leather is at the same time flexible to a degree notpresent in leather tanned by former processes. These two qualities render the leather produced by our rocess especially ap licable for the manuihcture of leather bets for power transmission purposes. v

The leather produced by our rocess also resists the action'of moisture an water containing chemicals in solution tov an unusual degree, which renders it well suited for use in ex osed positions.

n the use of our process it has been found that inferior hides, and such as are generally considered as incapable of being tanned by former processes, may by our process be successfully converted into leather.

While specific uses of the product produced by our rocesshave been. mentioned, it will of course e a preciated that the leather roduced may e used for any purpose for w ich leather is suitable. 4

\ Havin thus disclosed our invention and explaine in what manner the same is to be etters Patent:

The'method of tanning hides or skins after they have been subjected to a suitable preparatory treatment, which consists in treating them with a'solution formed from water, ferrous sulfate, potassium nitrate, and potassium bichromatein the proportion substantially as above set forth.

In witnessv whereof we have signed this specification in presence of two witnesses.

JIHACHI INOUYg. TSURUMATSU D GURA.

Witnesses:

REN YABE, UMAo ABE.

performed, we claim and desire to secure by 

